The invention relates generally to apparatus and methods for stripping insulated wires. More specifically, the invention relates to an apparatus and a method for stripping a magnet wire.
The term “magnet wire” as used herein is intended to mean an electrical wire fabricated by forming a polymer-based film, e.g., polyester-amide, polyester-amide-imide, polyimide, and polyurethane, on a solid conductor wire, where the polymer-based film serves as insulation. The polymer-based film provides a uniform dielectric coating without significantly increasing the overall diameter of the magnet wire. The thickness of the insulation formed on the conductor wire is known as build. The industry standards are as follows: single, heavy (or double), triple, and quad. Single and heavy builds are the most common. Table 1 below shows nominal dimensions for a copper magnet wire.
TABLE 1BareSingle BuildHeavy BuildSizeDiameterDiameterDiameter(AWG)(mm)(mm)(mm)260.40390.43180.4521300.25400.27690.2946350.14220.15750.1702400.07870.08890.0965440.05080.05590.0635
It is necessary to remove insulation from a section of a magnet wire to allow for soldering. The main difficulty in stripping a magnet wire is that the insulation layer is so thin that it is fairly easy to damage the conductor wire during insulation removal. For example, according to Table 1 above, a heavy-build 40 AWG magnet wire has an insulation thickness of about 0.0178 mm.
Prior-art mechanical stripping methods generally involve gripping the insulation wire at two places, severing the insulation between the two places with a pair of opposed blades selected for the gauge of wire, and pulling the severed insulation off the wire. Prior-art thermal stripping methods involve heating the opposed blades used in severing the insulation. These mechanical and thermal stripping methods are generally limited to large-diameter insulated wires, e.g., 30 AWG or larger. Chemical methods can be used to strip insulation wire provided that the wire is easily accessible.
From the foregoing, there is desired an apparatus and a method for stripping insulated wire regardless of wire diameter or accessibility.